Carbonated beverages are sold in glass and plastic containers which are pressurized and then sealed by original factory closures. The purpose of the closure is to seal the container and maintain the contents under pressure until the container is opened for dispensing the beverage. Some beverage containers are relatively small, in the six- to ten-ounce range, and are sealed by a disposable cap which is discarded after the beverage container is opened. Larger beverage containers, for example in the two- to three-liter range, are provided with re-usable screw cap closures for resealing the container after a portion of the beverage has been served.
Carbonated beverages typically contain dissolved carbon dioxide gas which will escape into the atmosphere unless the container is pressurized and sealed. The flavor of such carbonated beverages turns flat in the absence of the dissolved carbon dioxide gas. The loss of carbonation can be reduced somewhat by sealing the beverage container after use. However, because of the relatively large volume of some beverage containers, the carbonization will be released into the sealed open space within the container, with the result that the flavor of the remaining beverage is impaired. Accordingly, the quality of the beverage in such larger containers will gradually deteriorate, with the result that a substantial portion of the beverage will become unpalatable, and will be discarded.